Angular Distribution of Secondary Ions under FIB-shave-off Condition -Toward Development of Three-Dimensional Secondary Ion Image System-

摘要

In our previous studies, some approaches have been taken to get three-dimensional (3D) image for both inorganic and organic materials using FIB-ToF-SIMS technique. Of these, shave-off cross-sectioning and metal-assisted shave-off processes were predominant. In the present study, a further approach has been taken to get a 3D image through developing 3D shave-off cross-sectioning method for the generation of secondary ions. Currently used shave-off cross-sectioning method is able to provide 2D image on X-Z plane and that can be improved into 3D by using resistive anode detector through changing the optical transportation system of the secondary ions. Installation of cylindrical lens along Z-axis shows 1000 times magnification of the real image on the detector. For investigation of angular distribution of secondary ions, shape and/or angle of the shave-off cross-sectioning areas, using W-wires as model samples, was evaluated. Shave-off method exhibited the formation of a certain shape of the sample surface with 87° angle. The peak angle of the generated secondary ions was ~45° for 87° tilted samples (Si-wafer and Al-foil) and the observed secondary ion images were 2D by using a resistive anode detector. No significant change in angular distribution of the secondary ions was observed from highly roughness (Al-foil) and almost flat surfaces (Si-wafer).